Plug-in electric vehicles, including battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs), may be connected to an external power supply for charging a vehicle battery. Such vehicles typically include a charge cord that extends from an external power supply to transfer energy by inductive methods or by physical connection to a vehicle charging port to facilitate charging of the vehicle battery. The vehicle battery provides electrical power to operate a motor, which generates wheel torque for propelling the vehicle. When the battery charge is depleted, the vehicle may no longer be mobile, particularly with respect to BEVs. Economical driving choices can help extend the vehicle's range, particularly by reducing the rate at which the vehicle expends energy stored in the battery.
Vehicles include a number of interfaces, such as gauges, indicators, and/or displays to convey information to the driver regarding the vehicle and its surroundings. With the advent of new technologies, these interfaces have become more sophisticated. For example, some vehicles include battery state of charge gauges and vehicle range indicators. Also, many electric vehicles incorporate efficiency or economy gauges that attempt to convey a rate at which the vehicle is expending energy stored in the battery. Typically, these gauges utilize metrics unfamiliar to many drivers. As a result, these drivers struggle to relate to the rate of energy consumption in a meaningful way for evaluating vehicle operating efficiency.